fix(vat): complete account treatment enforcement (#1593)

* fix(vat): complete account treatment enforcement

* docs(api): refresh account endpoint skill

* fix(mcp): preserve ruta 05 compatibility

* test(vat): seed migration constraint fixtures

* docs(vat): clarify treatment precedence

---------

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

lib/pending-operations/__tests__/account-and-note-executors.test.ts

@@ -189,6 +189,51 @@ describe('commitPendingOperation: update_account', () => {
     expect(result.status).toBe('committed')
   })
 
+  it('derives an omitted booking rate at commit when the stored rate is unset', async () => {
+    const { supabase, enqueue, findCalls } = createQueuedMockSupabase()
+    enqueue({ data: { id: 'op-1' } }) // CAS claim
+    enqueue({ data: { default_vat_rate: null } }) // current account
+    enqueue({ data: { account_number: '4056', account_name: 'EU-varor', is_active: true } }) // update
+    enqueue({ data: null }) // finalize update
+
+    const op = makePendingOp({
+      operation_type: 'update_account',
+      params: {
+        account_number: '4056',
+        default_vat_treatment: 'reverse_charge_eu_goods',
+      },
+    })
+    const result = await commitPendingOperation(supabase as never, 'user-1', 'company-1', op)
+
+    expect(result.status).toBe('committed')
+    expect(findCalls('chart_of_accounts', 'update')[0]?.[0]).toMatchObject({
+      default_vat_treatment: 'reverse_charge_eu_goods',
+      default_vat_rate: 0.25,
+    })
+  })
+
+  it('preserves a stored booking rate when a staged treatment omits it', async () => {
+    const { supabase, enqueue, findCalls } = createQueuedMockSupabase()
+    enqueue({ data: { id: 'op-1' } }) // CAS claim
+    enqueue({ data: { default_vat_rate: 0.12 } }) // current account
+    enqueue({ data: { account_number: '4056', account_name: 'EU-varor', is_active: true } }) // update
+    enqueue({ data: null }) // finalize update
+
+    const op = makePendingOp({
+      operation_type: 'update_account',
+      params: {
+        account_number: '4056',
+        default_vat_treatment: 'reverse_charge_eu_goods',
+      },
+    })
+    const result = await commitPendingOperation(supabase as never, 'user-1', 'company-1', op)
+
+    expect(result.status).toBe('committed')
+    expect(findCalls('chart_of_accounts', 'update')[0]?.[0]).toEqual({
+      default_vat_treatment: 'reverse_charge_eu_goods',
+    })
+  })
+
   it('unknown account (PGRST116) auto-rejects with 404', async () => {
     const { supabase, enqueue } = createQueuedMockSupabase()
     enqueue({ data: { id: 'op-1' } }) // CAS claim

lib/pending-operations/commit.ts

@@ -128,6 +128,7 @@ import { CreateArticleParamsSchema, UpdateArticleParamsSchema } from '@/lib/pend
 import { CreateDimensionValueParamsSchema } from '@/lib/pending-operations/schemas/dimension-value'
 import { RetagLineDimensionsParamsSchema } from '@/lib/pending-operations/schemas/retag-line-dimensions'
 import { CreateAccountParamsSchema, UpdateAccountParamsSchema } from '@/lib/pending-operations/schemas/account'
+import { defaultRateForVatTreatment } from '@/lib/vat/account-vat-treatment'
 import { SetVoucherNoteParamsSchema } from '@/lib/pending-operations/schemas/voucher-note'
 import { UpdateCompanySettingsParamsSchema } from '@/lib/pending-operations/schemas/company-settings'
 import { UpdateCustomerParamsSchema } from '@/lib/pending-operations/schemas/customer'
@@ -946,6 +947,13 @@ async function commitCreateAccount(
   // Same row shape as the dashboard create route
   // (app/api/bookkeeping/accounts/route.ts): class/group/sort_order derive
   // from the number so the two write paths cannot drift.
+  const defaultVatRate = validated.default_vat_treatment && validated.default_vat_rate == null
+    ? defaultRateForVatTreatment(
+        validated.default_vat_treatment,
+        Number(validated.account_number[0]),
+      )
+    : validated.default_vat_rate ?? null
+
   const { data, error } = await supabase
     .from('chart_of_accounts')
     .insert({
@@ -962,7 +970,8 @@ async function commitCreateAccount(
       is_system_account: false,
       description: validated.description ?? null,
       default_vat_code: validated.default_vat_code ?? null,
-      default_vat_rate: validated.default_vat_rate ?? null,
+      default_vat_rate: defaultVatRate,
+      default_vat_treatment: validated.default_vat_treatment ?? null,
       sru_code: validated.sru_code ?? null,
       sort_order: parseInt(validated.account_number),
     })
@@ -1001,6 +1010,31 @@ async function commitUpdateAccount(
   for (const [key, value] of Object.entries(rest)) {
     if (value !== undefined) updateData[key] = value
   }
+
+  if (validated.default_vat_treatment && validated.default_vat_rate == null) {
+    const { data: current, error: currentError } = await supabase
+      .from('chart_of_accounts')
+      .select('default_vat_rate')
+      .eq('company_id', companyId)
+      .eq('account_number', account_number)
+      .single()
+
+    if (currentError) {
+      if (currentError.code === 'PGRST116') {
+        return { error: 'Kontot hittades inte', status: 404 }
+      }
+      return { error: currentError.message, status: 500 }
+    }
+
+    if (current.default_vat_rate == null) {
+      updateData.default_vat_rate = defaultRateForVatTreatment(
+        validated.default_vat_treatment,
+        Number(account_number.charAt(0)),
+      )
+    } else {
+      delete updateData.default_vat_rate
+    }
+  }
   if (Object.keys(updateData).length === 0) {
     return { error: 'Inget att uppdatera', status: 400 }
   }

lib/pending-operations/schemas/account.ts

@@ -1,4 +1,8 @@
 import { z } from 'zod'
+import {
+  ACCOUNT_VAT_TREATMENTS,
+  isVatTreatmentAllowedForAccountClass,
+} from '@/lib/vat/account-vat-treatment'
 
 // Commit-boundary re-validation for staged chart-of-accounts operations
 // (gnubok_create_account / gnubok_update_account). A staged
@@ -27,6 +31,8 @@ const defaultVatRate = z
   .nullable()
   .optional()
 
+const defaultVatTreatment = z.enum(ACCOUNT_VAT_TREATMENTS).nullable().optional()
+
 /** Empty string / null → undefined, then bounded string. */
 const optString = (max: number) =>
   z.preprocess((v) => (v == null || v === '' ? undefined : v), z.string().max(max).optional())
@@ -84,6 +90,7 @@ export const CreateAccountParamsSchema = z
     description: optString(2000),
     default_vat_code: optString(32),
     default_vat_rate: defaultVatRate,
+    default_vat_treatment: defaultVatTreatment,
     sru_code: optString(16),
   })
   .superRefine((v, ctx) => {
@@ -91,6 +98,19 @@ export const CreateAccountParamsSchema = z
     if (conflict) {
       ctx.addIssue({ code: 'custom', message: conflict, path: ['account_type'] })
     }
+    if (
+      v.default_vat_treatment &&
+      !isVatTreatmentAllowedForAccountClass(
+        v.default_vat_treatment,
+        Number(v.account_number[0]),
+      )
+    ) {
+      ctx.addIssue({
+        code: 'custom',
+        message: 'VAT treatment is not valid for this account class',
+        path: ['default_vat_treatment'],
+      })
+    }
   })
 
 export const UpdateAccountParamsSchema = z.object({
@@ -99,8 +119,23 @@ export const UpdateAccountParamsSchema = z.object({
   description: clearableString(2000),
   default_vat_code: clearableString(32),
   default_vat_rate: defaultVatRate,
+  default_vat_treatment: defaultVatTreatment,
   sru_code: clearableString(16),
   is_active: z.boolean().optional(),
+}).superRefine((v, ctx) => {
+  if (
+    v.default_vat_treatment &&
+    !isVatTreatmentAllowedForAccountClass(
+      v.default_vat_treatment,
+      Number(v.account_number[0]),
+    )
+  ) {
+    ctx.addIssue({
+      code: 'custom',
+      message: 'VAT treatment is not valid for this account class',
+      path: ['default_vat_treatment'],
+    })
+  }
 })
 
 export type CreateAccountParams = z.infer<typeof CreateAccountParamsSchema>